Control system with smart devices for hazardous environments

ABSTRACT

A control system for hazardous environments decreases flame paths, decreases punctures to the control system when installing interfaces, and increases safety. The control system may be characterized as a “one size fits all” controller that is able to automatically recognize a plurality of user interfaces. The controller has an enclosure to which the interfaces can be attached. The interfaces may interact with control electronics wholly contained in the enclosure using a variety of “wireless” mechanisms. Such mechanisms include reflecting light waves, infrared (IR) communication, radio-frequency identification, inductive coils, short-range wireless communication, camera images, piezoelectricity, and magnetism, and the like. The interfaces may include switches, indicator lights, smoke detectors, and the like.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 14/867,764, filed on Sep. 28, 2015 and entitled Control Systemwith Smart Devices for Hazardous Environments, the disclosure of whichis incorporated herein by reference.

BACKGROUND

This application relates generally to a control system, and morespecifically to a control system for various environments includinghazardous environments.

Present control systems are comprised of hundreds of components. Such alarge number of components complicates the manufacturing process andleads to increases in costs and time of manufacturing. Such complexityalso affects distributor's stock of components. Additionally, devicesused in current controllers have a significant number of flame paths.These flame paths decrease safety and can affect reliability of thedevices and controller.

BRIEF SUMMARY

According to one example described herein, a control system comprises:an enclosure comprising an opening on a front face and electronics forcontrolling a device; and at least one interface mounted to the frontface of the enclosure, which at least partially covers the opening andwhich is physically isolated from the electronics, wherein the at leastone interface is configured to communicate with the electronics.

In various embodiments of the above example, the enclosure has at leastone of an inlet and an outlet through which electronics or wiring of thedevice controlled by the control system pass; the enclosure has a lightsource and a light detector, and the interface is optically connected tothe electronics via the light source and the light detector; the atleast one interface comprises optical element for altering a path oflight emitted by the light source and a moveable aperture, the moveableaperture being movable to shield or expose the optical element inresponse to a mechanical actuation of the interface; when the opticalelement is exposed to light emitted by the light source, the light isreflected toward the light detector; and when the optical element isshielded from light emitted by the light source, the light is notreflected toward the light detector, wherein detection of reflectedlight by the light detector is indicative of a state of the interface;the electronics control at least one operation of a device based on thestate of the interface that corresponds to the device; the interfacecomprises pivotable or rotatable mirror, the mirror being pivotable orrotatable in response to an actuation of the interface; in a firstposition of the pivotable or rotatable mirror, light emitted by thelight source is reflected toward the light detector; and in a secondposition of the pivotable or rotatable mirror, light emitted by thelight source is not reflected toward the light detector, whereindetection of reflected light by the light detector is indicative of thestate of the interface; the electronics control a device based on thestate of the interface; the interface has a light mixing chamber and aclear cover for viewing light from the light source, the light sourcebeing operated in response to a status of a device controlled by thecontroller; the enclosure has a first inductive coil and/or a firstshort-range wireless device, the first short-range wireless device beinga receiver, transmitter, and/or transceiver, the interface has a secondinductive coil and/or a second short-range wireless device, the secondshort-range wireless device being a receiver, transmitter, and/ortransceiver, and the interface is wirelessly connected to theelectronics via the first inductive coil and/or the first short-rangewireless device; the first inductive coil and second inductive coil areshort-range wireless devices for transferring power and data; theinterface has a light source, light detector, and a moveable shield, themoveable shield being moveable into and out of a space between lightsource and the light detector in response to a mechanical actuation ofthe interface by a user to interrupt or allow transmission of light fromthe light source to the light detector; communication between the firstinductive coil and/or first short-range wireless device, and the secondinductive coil and/or second short-range wireless device is based onwhether light from the light source is detected by the light detector;the electronics control a device based on the communication; theinterface has a mechanical or electrical switch that is actuated betweena first state and a second state in response to a mechanical actuationof the interface by a user; communication between the first inductivecoil and/or first short-range wireless device, and the second inductivecoil and/or second short-range wireless device is based on the state ofthe switch; the electronics control a device based on the communication;the interface has a light source, a light mixing chamber, and a clearcover for viewing light from the light source, the light source beingoperated in response to communication between the first inductive coiland/or first short-range wireless device, and the second inductive coiland/or second short-range wireless device; the enclosure has a cameraconfigured to generate images of a pattern on the interface, the patternbeing rotated or otherwise altered in response to a mechanical actuationof the interface by a user; the electronics control a device based on ananalysis of pattern in the images; each of the at least one interfaceshas a unique identifier communicated to the electronics, such that theelectronics can automatically recognize the interface; the interface isa smoke detector, such that the interface detects smoke when lightemitted by the light source is not detected by the light detector; theenclosure is an explosion-proof enclosure for use in hazardousenvironments and physically isolates the at least one interface from theelectronics which reduces a number of flame paths associated with thesystem; the interface comprises a piezo-electric element that generatesa current upon actuation of the interface, and wherein the current isutilized for communication between the interface and the electronics;the interface comprises at least one magnetic element and at least onesensor, and wherein the sensor detects a magnetic flux caused byactuation of the magnetic element; the interface comprises a capacitivetouch element that generates a current upon actuation of the interface,and wherein the current is utilized for communication between theinterface and the electronics; the device may be controlled by aphysical user input at the at least one interface or automatically bycomparison of a signal value to a threshold.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1D is an illustration of perspective views of controllershaving zero, one, two, and three devices;

FIG. 2 is a cross-section of a controller illustrating three exampledevices;

FIG. 3 is a cross-section of a controller illustrating another threeexample devices; and

FIG. 4 is a cross-section of a controller illustrating another threeexample devices.

DETAILED DESCRIPTION

Certain terminology is used herein for convenience only and is not to betaken as a limitation on the claimed invention. Relative language usedherein is best understood with reference to the drawings, in which likenumerals are used to identify like or similar items. Further, in thedrawings, certain features may be shown in somewhat schematic form.

Generally, the controller can be described as comprising two aspects.According to a first aspect, the controller can be fitted with aplurality of devices, which may be auto-recognized by the controller.According to a second aspect, the interfaces (e.g., switches, actuators,relays, lights, and the like) associated with each of the plurality ofdevices are used to control and operate the respective devices.

Turning now to FIG. 1, a controller 100 has a box-shaped enclosure 102comprising an inlet 104, an outlet 106, and a front face 108. Theenclosure 102 may be, for example, a NEMA7 explosion-proof metallicenclosure. The inlet and outlet provide connections for devices operatedand controlled by the controller. A circuit board 210 comprising aprocessor(s) 212 and associated electrical components may be mountedwithin the enclosure 102. The components and processor 212 of thecircuit board 210 control the devices of the controller 100. Asillustrated in the figures, the inlet 104 and outlet 106 are provided onopposite sides of the controller enclosure 102. However, the shape andconfiguration illustrated in the figures is not intended to be limitingand it is noted that the controller 100 and enclosure 102 can take onany shape, size, or configuration. For example, in other embodiments(not illustrated), the enclosure may be a “back box” having a singleoutlet or inlet, or be a standalone box with no outlets or inlets.

With respect to the first aspect described herein, the front face 108 ofthe enclosure 102 may be fitted with a plurality of interfaces 110associated with devices of the controller 100. The front face 108provides an opening 112 to the interior of the enclosure 102 on whichthe plurality of interfaces 110 may be mounted across. The opening 112may be recessed into the enclosure 102 and a circuit board 210 may bepositioned within the recessed opening.

Each interface 110 may be mounted or installed by securing the interface110 to the exterior of the front face 102 of the enclosure 102 usingbolts, screws, adhesives, and the like. In this way, the interfaces 110fully extend over and cover the opening 112 along one direction.Additional interfaces 110 may cover or overlap the opening 112 along theother direction. Any portion of the opening 112 not covered byinterfaces 110 may be covered by patches or “blank” pieces and theseblanks maybe similar in size and/or shape to any of the interfacespresent thereon or may have a different appearance from the interfaces110. The interfaces 110 may also be collectively installed as singleunified piece that may completely cover the opening 112.

Each interface 110 may comprise substantially the same general sizeand/or shape relative to the opening 112 of the enclosure 102. In otherwords, each interface 110 may be installed or applied to the enclosure102 using a common form factor. This eliminates a need for uniquedrilling of the controller 100 and enclosure 102 to suit individualinterface 110 and device requirements. This further eliminatesadditional penetrations through the controller 100 and enclosure 102,thereby decreasing flame paths and improving safety.

Specific examples of interfaces according to the second aspect aredescribed herein with respect to FIGS. 2-4. According to a first exampleillustrated in FIG. 2, an interface 200 may comprise a stationary mirror202 and a movable aperture 204. While a mirror is described herein, itis noted that various embodiments could use any optical element that canalter a path of light, such as a lens or prism. A mechanical button(e.g., a spring biased push button) may be depressed to operate themovable aperture, so as to expose or shield the mirror. A light source(e.g., light emitting diode (LED) with narrow optics, such as acollimator) 206 and light detector 208 electrically connected to thecircuit board 210 and processor 212 may be located underneath the mirror202. The light source 206 and light detector 208 may be tunable toparticular wavelengths/bandwidths of light. In this way, a light waveemitted by the light source 206 is directed toward the mirror 202. Theinterface 200 may be operated (e.g., by a push button 214) to expose andshield the mirror 202 by moving the movable aperture 204. When theinterface 200 is operated such that the mirror 202 is exposed, the lightwave is reflected back toward the circuit board 210, where it isdetected by the light detector 208. Similarly, when the mirror 202 isshielded, light is neither reflected back toward nor detected by thelight detector 208. In some embodiments, operation or actuation of theinterface 200 may operate to alter light emitted by the light source 206such that only a particular wavelength/bandwidth of light reaches thelight detector 208. Thus, each scenario as described (e.g., lightdetected, no light detected, particular wavelength/bandwidths of lightdetected) may be associated with a state of the interface 200. Thedepression of the button 214 of the interface 200 changes the state ofthe interface 200, thereby controlling or determining a current state ofthe interface 200. Depending on whether light is detected by the lightdetector 208, the processor(s) 212 may appropriately operate anassociated device according to a desired function controlled by theinterface 200. In other words, for example, a first state of theinterface 200 may be intended to cause a device to turn-on and a secondstate of the interface 200 is intended to cause a device to turn-off. Inthis instance, when the light detector 208 indicates a first state ofthe interface 200, the processor 212 may cause the device to turn on.Similarly, when the light detector 208 indicates a second state of theinterface 200, the processor 212 may cause the device to turn off.

In another example, also illustrated in FIG. 2, an interface 220comprises a pivoting mirror 222, a shaft 226 and a button 228. The shaft226 extends from and is engaged with the button 228. The pivoting mirror222 pivots or rotates about the shaft 226 of the interface 220 when thebutton 228 is depressed and maintained in this depressed position. Theinterface 220 may also comprise a diaphragm 224 that environmentallyseals the mirror 222 from the button 228. The mirror 222 may be biasedto a position substantially orthogonal to the shaft 226 where lightwaves from a light source 206 may be reflected back toward a lightdetector 208 (as described above). Thus, as the button 228 is depressedand the shaft 226 extends away from the diaphragm 224, the mirror 222pivots toward a reflecting position (not shown) whereby light isreflected toward the light detector 208. When the button 228 isdepressed again (e.g., to release the button), the shaft 228 and mirror222 rise toward the diaphragm 224. The diaphragm 224 may then provide aforce to pivot the mirror 222 to a substantially parallel position withthe shaft 228. In this substantially parallel position, no light wavesare reflected back toward the light detector 208. In this way, thebutton 228 of the interface 220 and detection of reflected light by thelight detector 208 may operate a device in a manner substantiallysimilar to that described above with respect to interface 200.

It should be noted that the above two examples are not intended to belimiting. Rather, any mechanical mechanism for shielding and exposing astationary mirror, and/or pivoting or rotating a mirror so as to causean emitted light wave to be reflected toward a light detector toindicate a state of an interface, is intended to be within the scope ofthe present disclosure.

Another interface 240, as illustrated in FIG. 2, is a light that mayserve as an indicator or visual signal regarding the state of acontrolled device(s) or other interface. The interface 240 may comprisea light pipe or light mixing chamber 242. A light wave or light wavesemitted from one or a plurality of light sources 206 (e.g., LEDs ofvarying colors) may be directed into the light pipe 242. If light wavesof various wavelengths enter the light pipe 240, they may be mixed toform a new color. The light in the light pipe 242 may then be visiblethrough an opening or diffused or clear cover 244 of the interface 240.In this way, the light source(s) 206 may be electrically connected tothe processor 212 of the circuit board 210 and may be operated accordingto logic indicating a current state of a device or other interface.

FIG. 3 illustrates a plurality of example interfaces (300, 320, 340)that use inductive power and wireless communication. The wirelesscommunication can be, for example, short-range communication such asBluetooth®. According to a first example, an interface 300 comprises abutton 302 connected to a shield 304, a light source 306 (e.g., an LED),a light detector 308, an inductive coil 310, and a Bluetooth®transceiver 312. The light source 306 and light detector 308 arearranged across from each other in the interface 300. Similar to theexamples described above with respect to FIG. 2, as the button 302 isdepressed, the shield 304 passes between the light source 306 and lightdetector 308 so as to disrupt communication of a light wave from thelight source 306 to the light detector 308. When the button 302 ispressed again, the shield 304 may rise above the light source 306 andlight detector 308 so as to allow the communication of light between thelight source 306 and the light detector 308. In this way, the detectionof light, or lack of detection of light (e.g., in the absence of lightdetection), by the light detector 308 can indicate a state of the button302 and consequently, a state of the interface 300. The light detector308 can be electrically connected to the inductive coil 310 and/orBluetooth® transceiver 312, such that the inductive coil 310 and/orBluetooth® transceiver 312 can be operated according to a state of theinterface 300.

As with the first example of FIG. 3, a second example interface 320 ofFIG. 3 comprises a button 322 connected to a post 324, a mechanicalswitch 326, an inductive coil 328, and a Bluetooth® transceiver 330.Rather than using an optical switch to control operation of theinductive coil 328 and/or Bluetooth® transceiver 330 as described above,the second example uses a mechanical switch 326. More specifically, asthe button 322 is depressed, a beveled edge of the post 324 slidesacross the mechanical switch 326, thereby depressing the switch 326.However, in other embodiments, it is envisioned that the post 324 may beconductive so as to close a path between contacts as the button 324 isdepressed. In still other embodiments, the post 324 may act as a firstcontact and, upon depression of the button 324, make contact with asecond contact to close the switch. In any case, the state of the switch326 is indicative of the state of the button 322, and the state of thebutton 322 is indicative of the state of the interface 320. Thus, theswitch 326 is electrically connected to the inductive coil 328 and/orBluetooth® transceiver 330 so as to control the operation of theinductive coil 328 and/or Bluetooth® transceiver 330 based on the stateof the interface 320.

A corresponding inductive coil(s) 332 and/or Bluetooth® transceiver(s)334 are mounted to the circuit board 210 and are electrically connectedto the processor(s) 212. The inductive coil 332 and/or Bluetooth®transceiver 334 of the circuit board 210 can then communicate with theinductive coil(s) 310, 328 and/or Bluetooth® transceiver(s) 312, 330 ofthe interfaces 300, 320 based on the state of the interfaces 300, 320.In this way, the interfaces 300, 320 may operate and control the devicesof the controller, as well as receive information from or about thedevices of the controller, without being physically connected to thedevices, circuit board 210, or interior of the enclosure 102. As withthe examples described in FIGS. 2 and 3, the interfaces 200, 220, 240,300, 320 are situated separate and apart from the interior of theenclosure 102, and the circuit board 210 is isolated within the interiorof the enclosure 102, thereby increasing safety.

A third example of an interface 340 illustrated in FIG. 3 is anindicator light. The indicator light comprises an inductive coil 342, aBluetooth® transceiver 344, a control 346, a light source (e.g., LED)348, and a light pipe or light mixing chamber 350. The control 346 iselectrically connected to the inductive coil 342, Bluetooth® transceiver344, and light source 348. The indicator light interface 340 operates ina similar, but reversed, manner to the previous two examples of FIG. 3.That is, the inductive coil 342 and/or Bluetooth® transceiver 344receive signals from an inductive coil 332 and/or Bluetooth® transceiver334 on the circuit board 210. Based on the signals received therefrom,the control 346 operates the light source 348 so as to emit a lightcorresponding to or determined by the received signal. The light may beviewed through an opening or transparent/clear cover 352 of theinterface 340. For example, a signal indicating a device status (e.g.,power on or error) may be sent to the inductive coil 342 and/orBluetooth® transceiver 344 of the interface 340. The control 346 mayinterpret this error signal and cause the light source 348 to output acolored light corresponding to the determined state or status of adevice. In other embodiments, actuation of an interface may cause achange detectable by the control 346. For example, actuation of aninterface could move an inductor thereby changing the efficiency of thesystem indicating a change to a device status or state. Such a changecould be interpreted by software of the control 346, or otherwisedetected by a hardware sensor element that provides an input to thecontrol 346. For example, the detection could be the result ofcomparison to a threshold value. Thus, the actuation results in a changein the operation of the light source 348 by the control 346 according toa state or status of a device. In response to the input, the control 346may also actuate a device (e.g., a relay or contact). In this way, thecontrol 346 can operate to cause a status or state change and/or thenindicate the result of the change.

Still another example of an interface 400 is illustrated in FIG. 4. Inthe example of FIG. 4, a pattern 402 is disposed on an underside of abutton 404 (or post of a button) of the interface 400. A camera 406mounted to the circuit board 210 and electrically connected to theprocessor(s) 212 is directed to capture images of the pattern 402. Asthe button 404 is depressed, the pattern 402 (and/or post on which thepattern is disposed) may be rotated or otherwise altered. By processingthe captured images to determine the pattern 402 or orientation of thepattern 402, the processor 212 can determine the state of the interface400. As with the other interfaces already described, the recognition ofthe state of the interface can be used to control a correspondingdevice.

While the above interfaces have been described as examples, it is notedthat these are not intended to be a limiting or inclusive list of suchinterfaces. For example, a light source and light detector as discussedwith respect to FIGS. 2 and 3 may be used as a smoke detector. That is,a light source may emit a light wave directly toward a light detector ortoward a mirror such that the reflection directs the light wave toward alight detector, where failure of the light wave to reach the lightdetector would indicate the presence of interference such as smoke.Thus, if the light detector fails to detect a light wave or if thedetected light has an intensity level below a predetermined thresholdvalue, an alarm or other warning may be sounded indicating the presenceof smoke in the enclosure of the housing. In still other variations ofthe above examples, infrared (IR) emission and/or radio frequencyidentification (RFID) may be used instead of, or in addition to, theoptical mechanisms, inductor coils, and Bluetooth® transceivers.

Still other interfaces may use piezo-electric and/or magnetic actuation.For example, in a piezoelectric interface, a push button could be usedto compress a piezoelectric element, thereby generating an electriccurrent. This current could be used to activate a light source,inductive coil, Bluetooth® transceiver, or the like. Regarding magneticactuation, a magnetic interface could take advantage of opposing magnetsto actuate electrical contacts, without being in physical contact withthe electrical contacts. Such a mechanism is described, for example, inU.S. application Ser. No. 14/026,583, which is herein incorporated byreference. Still other embodiments could utilize sensors to detectactuation of a magnetic interface by detecting a magnetic flux caused bythe actuation.

The above described interfaces, and other interfaces envisioned withinthe scope of the present disclosure, may be automatically recognized bythe controller. For example, each interface may have a uniqueidentifying signal output that may be recognized by the processor in thecontroller. Such signals may be generated according to a reflected lightwave pattern, IR pattern, inductive coil transmission, Bluetooth®transmission, RFID, or the like. In this way, the controllers could befurther easily assembled by using a standard processor and interiorelectronics that do not require reconfiguration or reprogramming basedon the desired interface(s) used for each controller.

It is also noted that the interfaces may be potted with athermos-setting plastic, silicone, or the like so as to resistvibrations, prevent shocks, and further help isolate the interface fromthe interior of the enclosure.

A “processor” as used herein refers to any, or part of any, electricalcircuit comprised of any number of electrical components, including, forexample, resistors, transistors, capacitors, inductors, and the like.The circuit may be of any form, including, for example, an integratedcircuit, a set of integrated circuits, a microcontroller, amicroprocessor, a collection of discrete electronic components on aprinted circuit board (PCB) or the like. The processor may also standalone or be part of a computer used for operations other than processingimage data. It should be noted that the above description isnon-limiting, and the examples are but only a few of many possibleprocessors envisioned.

What is claimed is:
 1. A control system, comprising: a controllercomprising: an enclosure; and electrical components positioned withinthe enclosure; and at least one interface comprising a mechanicalswitch, wherein the at least one interface and mechanical switch aremounted to an external face of the enclosure such that the mechanicalswitch is positioned exterior to the enclosure, wherein the at least oneinterface is physically isolated from the electrical components, whereinthe electrical components positioned within the enclosure can detectactuation of the mechanical switch without being in physical contactwith the mechanical switch, and wherein the at least one interfacecomprises an optical element for altering a path of light emitted by alight source and a moveable aperture, the moveable aperture beingmovable to shield or expose the optical element in response to theactuation of the mechanical switch.
 2. The control system of claim 1,wherein the enclosure has at least one of an inlet and an outlet throughwhich electronics or wiring of a device controlled by the control systempass.
 3. The control system of claim 1, wherein: the enclosure has thelight source and a light detector, and the at least one interface isoptically connected to the electrical components via the light sourceand the light detector.
 4. The control system of claim 3, wherein the atleast one interface is a smoke detector, such that the at least oneinterface detects smoke when light emitted by the light source is notdetected by the light detector.
 5. The control system of claim 1,wherein: when the optical element is exposed to light emitted by thelight source, the light is reflected toward the light detector; and whenthe optical element is shielded from light emitted by the light source,the light is not reflected toward the light detector, wherein detectionof reflected light by the light detector is indicative of a state of theat least one interface.
 6. The control system of claim 1, wherein theelectrical components control at least one operation of a device basedon the state of the at least one interface.
 7. The control system ofclaim 1, wherein the at least one interface is removable from externalface of the enclosure.
 8. The control system of claim 1, wherein the atleast one interface has a unique identifier communicated to theelectrical components, such that the electrical components canautomatically recognize the at least one interface.
 9. The controlsystem of claim 1, wherein the enclosure is sealed such that no flamepaths exist between the at least one interface and the electricalcomponents.
 10. The control system of claim 1, wherein the at least oneinterface comprises a piezo-electric element that generates a currentupon actuation of the at least one interface, and wherein the current isutilized for communication between the at least one interface and theelectrical components.
 11. The control system of claim 1, wherein the atleast one interface comprises at least one magnetic element and at leastone sensor, and wherein the at least one sensor detects a magnetic fluxcaused by actuation of the at least one magnetic element.
 12. Thecontrol system of claim 1, wherein the at least one interface comprisesa capacitive touch element that generates a current upon actuation ofthe at least one interface, and wherein the current is utilized forcommunication between the at least one interface and the electricalcomponents.
 13. The control system of claim 1, wherein a device may becontrolled by a physical user input at the at least one interface orautomatically by comparison of a signal value to a threshold.
 14. Acontrol system, comprising: a controller comprising: an enclosure havinga light source and a light detector; and electrical componentspositioned within the enclosure; and at least one interface comprising amechanical switch, wherein the at least one interface is mounted to anexternal face of the enclosure, wherein the at least one interface isphysically isolated from the electrical components and opticallyconnected to the electrical components via the light source and thelight detector, and wherein the electrical components can detectactuation of the mechanical switch, wherein the at least one interfacecomprises a pivotable or rotatable mirror, the mirror being pivotable orrotatable in response to the actuation of the mechanical switch.
 15. Thecontrol system of claim 14, wherein: in a first position of thepivotable or rotatable mirror, light emitted by the light source isreflected toward the light detector; and in a second position of thepivotable or rotatable mirror, light emitted by the light source is notreflected toward the light detector, wherein detection of reflectedlight by the light detector is indicative of a state of the at least oneinterface.
 16. The control system of claim 15, wherein the electricalcomponents control a device based on the state of the at least oneinterface.
 17. A control system, comprising: a controller comprising: anenclosure having a light source and a light detector; and electricalcomponents positioned within the enclosure; and at least one interfacecomprising a mechanical switch, wherein the at least one interface ismounted to an external face of the enclosure, wherein the at least oneinterface is physically isolated from the electrical components andoptically connected to the electrical components via the light sourceand the light detector, and wherein the electrical components can detectactuation of the mechanical switch, wherein the at least one interfacehas a light mixing chamber and a clear cover for viewing light from thelight source, the light source being operated in response to a status ofa device controlled by the controller.
 18. A control system, comprising:a controller comprising: an enclosure; and electrical componentspositioned within the enclosure; and at least one interface comprising amechanical switch, wherein the at least one interface and mechanicalswitch are mounted to an external face of the enclosure such that themechanical switch is positioned exterior to the enclosure, wherein theat least one interface is physically isolated from the electricalcomponents, and wherein the electrical components positioned within theenclosure can detect actuation of the mechanical switch without being inphysical contact with the mechanical switch, and wherein the enclosurehas a camera configured to generate images of a pattern on the at leastone interface, the pattern being rotated or otherwise altered inresponse to the actuation of the mechanical switch.
 19. The controlsystem of claim 18, wherein the electrical components control a devicebased on an analysis of pattern in the images.